I guess I'm not adding much to your comment, but I just wanted to remark that this exact thing has been bugging me for ages: people talk about these blockchain projects as being "decentralized" simply because _execution of the algorithm_ is distributed across lots of (mutually distrusting) nodes. This perspective confuses me, because it doesn't seem to be a particularly meaningful distinction when there is still one consensus truth in the network.
In the case of a naming system, as you point out, that means there is still one finite, scarce namespace in the system, just as there is in DNS.
More generally, there is still a central authority pushing out code, and so unless you want to hard-fork, what does the "decentralization" in a blockchain actually buy you? Does it do anything more for you in practical terms than protecting you from a central server suffering an outage?
I spent some time a while back coming up with ideas for an alternative to blockchains that would pursue many of the same goals, starting from first principles ("what the heck even _is_ money?"). I have no idea whether any of my ideas would have actually worked in practice, but they at least ticked the "decentralized" box in a way that I found a lot more meaningful than merely "decentralized execution of a centrally-defined algorithm to determine a single global consensus state". (I stopped working on them not because they didn't show promise, but because I became convinced that they would be a net negative for the world if they were successful; I lost the desire to find a working design.)